Representative turbine constructions employing sideplates of the general type taught herein are illustrated in U.S. Pat. No. 3,096,074 to Pratt et al. entitled "Bladed Rotors of Machines Such as Gas Turbines" and U.S. Pat. No. 4,019,833 to Gale entitled "Means for Retaining Blades to a Disc or Like Structure". In such structures a plurality of rotor blades extend outwardly from a supporting disk across a flowpath for working medium gases. Each blade has a root section which engages the supporting disk at an essentially axial slot of complex geometry. A slight gap at the interface between the root section of the blade and the disk is provided to enable assembly of the blade into the disk slot. Under centrifugal forces in an operating machine the blade is urged outward within the slot to a point of restraint. Undesirably, the gap at the interface becomes large enough to induce the leakage of medium gases therethrough with a resultant degradation of engine performance. Disk sideplates are conventionally provided to cover the interfaces between the blades and the disk for the prevention of such leakage. The sideplates perform the additional function of axially retaining the root sections of the blades in the corresponding slots.
In structures of both the Pratt et al and Gale patents, one-piece sideplates are employed. Various interlocking tabs hold the sideplates against the rotor disk. Notwithstanding the availability of structures of the above type, improvements to sideplates and corresponding attaching structures are continually sought.